// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/test/mock_log.h"

namespace base {
namespace test {

    // static
    MockLog* MockLog::g_instance_ = nullptr;
    Lock MockLog::g_lock;

    MockLog::MockLog()
        : is_capturing_logs_(false)
    {
    }

    MockLog::~MockLog()
    {
        if (is_capturing_logs_) {
            StopCapturingLogs();
        }
    }

    void MockLog::StartCapturingLogs()
    {
        AutoLock scoped_lock(g_lock);

        // We don't use CHECK(), which can generate a new LOG message, and
        // thus can confuse MockLog objects or other registered
        // LogSinks.
        RAW_CHECK(!is_capturing_logs_);
        RAW_CHECK(!g_instance_);

        is_capturing_logs_ = true;
        g_instance_ = this;
        previous_handler_ = logging::GetLogMessageHandler();
        logging::SetLogMessageHandler(LogMessageHandler);
    }

    void MockLog::StopCapturingLogs()
    {
        AutoLock scoped_lock(g_lock);

        // We don't use CHECK(), which can generate a new LOG message, and
        // thus can confuse MockLog objects or other registered
        // LogSinks.
        RAW_CHECK(is_capturing_logs_);
        RAW_CHECK(g_instance_ == this);

        is_capturing_logs_ = false;
        logging::SetLogMessageHandler(previous_handler_);
        g_instance_ = nullptr;
    }

    // static
    bool MockLog::LogMessageHandler(int severity,
        const char* file,
        int line,
        size_t message_start,
        const std::string& str)
    {
        // gMock guarantees thread-safety for calling a mocked method
        // (https://github.com/google/googlemock/blob/master/googlemock/docs/CookBook.md#using-google-mock-and-threads)
        // but we also need to make sure that Start/StopCapturingLogs are synchronized
        // with LogMessageHandler.
        AutoLock scoped_lock(g_lock);

        return g_instance_->Log(severity, file, line, message_start, str);
    }

} // namespace test
} // namespace base
